This study comprised three questions, each posed with the intention of exploring the expression of the neurofilament protein (NF) and mRNA levels in the monkey lateral geniculate nucleus (LGN) and visual cortex. (1) Literature indicates NFs are differentially expressed across the two visual pathways that originate from magnocellular and parvocellular layers in LGN. The results herein suggest that this difference continues at the level of gene transcription for the neurofilament heavy gene. (2) NF expression, assessed by SMI-32 (an antibody that recognizes an epitope of the non-phosphorylated NFs), was investigated as a function of developmental changes occurring during the critical period in area V1 of the vervet monkey visual cortex. The findings indicate that the M pathway develops before the P pathway. (3) The effect of eye enucleation on long-term changes in NF expression was investigated. The results do not support the idea that NF are activity-dependent.

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A series of studies is described here which explore the functional organisation of face- and object-processing neurones in the adult vervet monkey brain. This fundamental issue in high-level vision is addressed by the use of a novel molecular mapping technique that was developed for this purpose. / In the first study, the temporal dynamics of c-fos and zif268 expression were delineated in detail in the rat visual cortex. Knowing the precise temporal parameters of up-regulation (after onset of sensory stimulation) and down-regulation (after offset of sensory stimulation) of these genes was integral to optimising the temporal aspects of the stimuli to be used for subsequent mapping experiments. This study provided the critical information for devising stimuli with corresponding temporal parameters to those of c-fos or zif268 so that one could take advantage of the disparity between the expression of their mRNA and protein products in order to visualise activated neurones. / In the second study, the newly developed molecular mapping technique was validated in the rat auditory, visual and multisensory systems. First, bimodal audiovisual stimuli were designed using the data obtained from the first study. Then, through the combined histological detection of the mRNA and protein products of zif268, discrete populations of neurones responsive to either component of the bimodal stimulus were visualised. It was also observed that a third population of neurones was found that responded to the stimulation through both sensory modalities. The combined results from these two studies set the stage for addressing the issue of the organisation of face- and object-selective neurones of the inferior temporal cortex in the vervet monkey brain. / In the third study, the functional organisation of face- and object-selective neurones was examined using the molecular mapping technique. Based on the data gathered from the first two studies, suitable stimuli containing two distinct object classes (conspecific faces and non-face familiar objects) were designed with appropriate temporal parameters. / Finally, the last study provided an opportunity to address the issue of hemispheric asymmetry of function in the context of face processing in the non-human primate brain. Results support the notion that there may indeed be phylogenetic explanations for the hemispheric asymmetry observed in the human brain.

No description available.